Japan warned China on Tuesday that ties were deteriorating over the disputed East China Sea islets while China's envoy in Tokyo, reiterated its stand on the territorial claims and called for talks to resolve the matter.

The conflict between Asia's two largest economies has been strained recently since Japan saw an increasing number of Chinese coast guard and other government ships sailing near the disputed islets of Senkaku in Japan and Diaoyu in China.

A Japanese Foreign Ministry statement said that Fumio Kishida, the Japanese Foreign Minister, told Chinese ambassador Cheng Yonghua on Tuesday that Beijing was trying to change the status quo unilaterally.

Kishida also told the Chinese envoy that the ambience related to Sino-Japanese ties was "deteriorating markedly", the statement said.

After the discussion, Cheng said that he told Kishida about the islets being an integral part of China's territory.

"I told him that... it is natural that Chinese ships conduct activity in the waters in question," Cheng told Reuters.

"I also told him both countries need to work on dialogue through diplomatic channels so as not to make things more complicated and escalated," he added.

Japanese Foreign Ministry officials had repeatedly protested over "intrusion" of Chinese ships in their claimed territorial waters of the rocky islands.

Vice-Foreign Minister Shinsuke Sugiyama also called Cheng on Friday after two Chinese coast guards and several fishing vessels entered the territorial waters.

On Tuesday, the Japanese coast guard again spotted several Chinese ships in the disputed water and dozen other vessels nearby the islands.

Similar incidents were reported on Monday and Sunday as well.

Kyodo News in Japan reported on Monday that the nation wants "high- level" talks with China regarding this "intrusion" issue which is continuing despite Tokyo's protest.